Provides hotkey support for piazza. Paste into the Chrome Dev Console for use. This fork changes the keycodes to Gmail/Vim defaults.

piazza_hotkeys.js

(function() {
    /*
     Provides hotkey support for navigating many posts on piazza.
        1) e + alt: archives the current post and navigates to the previous post
        2) u + alt: marks the current post as unread and navigates to the previous post
        3) k + alt: navigates to the more recent post from current
        4) j + alt: navigates to the older post
    */
    // keycodes: http://keycode.info/
    const keyArchive = 69; // alt + e
    const keyUnread = 85; // alt + u
    const keyGoUp = 75; // alt + k
    const keyGoDown = 74; // alt + j
    const getSelected = function() {
        s = document.querySelectorAll("li.selected");
        return s.length > 0 ? s[0] : null;
    };
    document.addEventListener("keydown", function(event) {
        const code = event.keyCode;
        const alt = event.altKey;
        if ( (code == keyArchive || code == keyUnread) && alt)  { // alt key is pressed
            var split = window.location.search.split("=");
            var questionID = split.length > 1 ? split[split.length - 1] : "?";
            var current = getSelected();
            if (current) {
                var prev = current.previousElementSibling;
                var dropdown = document.getElementById('FeedItemDropdown_' + current.id);
                if (code == keyArchive) {
                    var archive = dropdown.children[1].children[1];
                    archive.click();
                    if (!archive) {
                        console.log('Failed to archive post ' + questionID);
                    }
                }
                else {
                    var unread = dropdown.children[1].children[3];
                    unread.click();
                    if (!unread) {
                        console.log('Failed to mark post ' + questionID + 'as unread');
                    }
                }
                if (prev) { // go to the next most recent post.
                    prev.click();
                }
            }
            else {
                console.log("Did not select a question");
            }
        }
        else if ( (code == keyGoUp || code == keyGoDown) && alt) { // up + alt, keyGoDown + alt
          event.preventDefault();
          current = getSelected();
          if (current) {
            if (code == keyGoUp) {
                current.previousElementSibling.click();
            }
            else {
                current.nextElementSibling.click();
            }
          }
          else {
            console.log("No question selected");
          }
        }
        else {
            // pass
        }
    });
})();

piazza_hotkeys.min.js

// Prepend `javascript:` to save this as a bookmarklet.
!function(){const e=function(){return s=document.querySelectorAll("li.selected"),s.length>0?s[0]:null};document.addEventListener("keydown",function(l){const n=l.keyCode,o=l.altKey;if(69!=n&&85!=n||!o)75!=n&&74!=n||!o||(l.preventDefault(),(c=e())?75==n?c.previousElementSibling.click():c.nextElementSibling.click():console.log("No question selected"));else{var t=window.location.search.split("="),i=t.length>1?t[t.length-1]:"?",c=e();if(c){var s=c.previousElementSibling,d=document.getElementById("FeedItemDropdown_"+c.id);if(69==n){var r=d.children[1].children[1];r.click(),r||console.log("Failed to archive post "+i)}else{var a=d.children[1].children[3];a.click(),a||console.log("Failed to mark post "+i+"as unread")}s&&s.click()}else console.log("Did not select a question")}})}();